Island



(No Model.)

J. P. THAYER.

WOOD SCREW.

N0. 391,097. Patented Oct. 16, 1888.

t w l NVEN TDR.

Warren STATES ATENT OFFICE.

JAMES F. THAYER, OF PROVIDENCE, RHODE ISLAND.-

WOOD-SCREW.

SPECIFICATION forming part of Letters Patent No. 391,097, dated October 16, 1888.

Application filed January l1, 188B. Serial No. 20,394. (No model.)

To all whom t may concern.-

Be it known that I, JAMES F. THAYER, a citizen of the United States, residing at Provi dence, in the county of Providence and State of Rhode Island,have invented certain new and useful Improvements in Screws; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled inthe art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters and gures of reference marked thereon, which form a part of this specification.

Screws as commonly made have the heads nicked or slotted for the insertion of a screwdriver. Ihe lower end portion of the blade of such screw-driver is generally somewhat tapering or slightlyr wedge-shaped, thereby adapting it to enter the nick more readily. From the fact, however, that the outer edges of the nicks are square or angular the action of the blade of the screw-driver in turning the screw soon produces a burr or roughness along such edges, which is removed by a subsequent operation of filing or grinding when deemed necessary. It is obvious, in the event of screws having finished and plated heads, that such burr or roughness of the nick becomes particularly undesirable or objectionable, because of the impossibility of its removal without, in a great degree, injury to 'the finished surface.

The object of my present improvement is to produce a screw in which the disadvantages and objections before referred to are overcome. To this end I provide the head of the screw with a nick having the outer parallel edges thereof cut away or chamfered or rounded. By means of this novel feature in the construction of screw-heads the blade of the screw-driver is more readily guided into and centered in the screw-nick. Moreover, the action of the screw-driver-as in forcing the improved screw home-does not injuriously affect the nick or produce an unsightly appearance.

In the accompanying drawings, Figure l represents a perspective view of an ordinary screw, but having the head thereof provided with a nick whose opposite corners or edges are rounded or chamfered according t) my invention. Figs. 3 and 4 are similar views of the upper portion of screws having a different form of head, although provided with my improved nick. Fig. 2 is a top plan View of Fig. 1. Fig. 5 is a View of the head portion of an ordinary wood-screw, the edges of the nick, however, being beveled. Fig. 6 is a view of the head portion of a screw of usual construction, the nick being as common. Fig. 7 shows a milling tool cutting my improved nick. Fig. 8 represents a screw-head having my improved nick formed therein by means of a hammer, as in heading.

Referring again to the drawings,a designates an ordinary form of woodscrcw having my improved nick.

s indicates the shank of the screw. the same having its lower portion screw-threaded, as at t. The upper portion of the shank terminates in a hcad,l1.. The form of the head may be conical, oval, cylindrical, Svc., as indicated in the drawings.

The screws have a nick or cut formed across the face of the head adapted to receive a screwdriver. The usual form of niek is indicated at n, Fig. 6. The upper surface of the head contiguous to the nick on each side is substantially at right angles therewith, as at b.

My improvement consists, chiefly, in providing screws with nicks n, having the outer edges thereof removed, as at c. In Figs. l to 4, inclusive, this portion of the nick is shown rounded, while in Fig. 5 the corresponding edges are shown beveled or chamfered. In Fig. 3 the lower or bottom edges or corners of the nick, as at c', are represented as rounded, thereby increasing materially the strength of the screw-head. The vertical edges of the nick may also be chamfered, as at c2, Figs. l and 2, thereby adding to the value of the screw, as hereinbefore described with reference to the outer lateral edges, c, of the nick.

The operation of forming my improved nick is illustrated in Fig. 7-by subjecting the head of the screw to arapidly-revolving millingtool or cutter, m, which cuts the nick in the usual 1nanner,and at the same time chamfers the corners and edges of the nick, the t-ool or cutter m being in cross section correspondingly formed to that of the nick.

In place of forming the nick as above de- IOO scribed, the operation may be performed by means of a hammer, indicatedI as 1 in Fig. 8,

'said hammer having a tongue, 2, projecting from the lower surface thereof and provided with rounded corners and edges 3 3 and 4:, which enter the nick n of the screw-head,while the body s of the screw is confined in the dieblock 5 in the usual manner, and a pressure being applied to said hammer the corners of the nick are correspondingly rounded or chamfered by contact with the corners of the tongue 2 of said hammer. y Y

Other means for performing the operation of forming my improved nick might be suggested. The above are given simply for the purpose of illustrating my improvement.

The hammer shown and briey described herein is not claimed in this application, but

is made the subject-matter for another filed simultaneously herewith.

I claim as myinventionl. As'an improved article of manufacture,

a screw having the lateral edges of the nick rounded or chamfered, substantially as described, and for the purpose specified.

2. A screw having the slot or nick formed in its head for the reception of a screw-driver rounded or chamfered off along its edges, subv stantially as hereinbefore described, and for the purpose set forth.

3. A sicrew having a slot or nick formed in its head, the edgesiand corners of said slot or nick being rounded or chamfered, substan-` tially as set forth.

4. The screw hereinbefore described,having the head thereof provided with a nick, n, whose lateral edges, as c, are rounded or chamfered, substantially as shown, and for the purpose set forth.

In testimony whereof I afix mysignaturc in the presence of two witnesses.

JAMES F. THAYER..v

Witnesses:

F. A. SMITH, Jr., CHARLEs GREENE. 

